Enable context menu icon.

[chenba]

Fixes #3858

[jaredhirsch]

@chenba This change looks good, but I suspect adding the icon to the manifest may impact Talos performance. Would you be up for testing this patch on the Try server?

If you'd like to learn to do the export, this is a good opportunity; you wouldn't need to mess with changelog generation or tagging, but just run the export script (EXPORT_MC_LOCATION=path/to/gecko ./bin/export_mc.py --no-commit --no-switch-branch). If you'd like to skip that step, this is a very small patch, so it'd be fine to directly edit the files inside mozilla-central, then commit inside m-c, and push to Try.

Whichever approach you opt for, I'd suggest the incantation from the export doc: ./mach try -b o -p linux64,macosx64,win32,win64 -u all -t all --rebuild-talos 5 --no-artifact.

[jaredhirsch]

I forgot to mention that the export documentation is inside /docs.

[chenba]

Yep, no prob. Already used the export script for #3967

What's the alternative if there's a performance regression? Try different image formats?

[jaredhirsch]

What's the alternative if there's a performance regression? Try different image formats?

Probably best to just ask the addons team if we see a regression; they might fix it themselves, or offer us a workaround. In the past, regressions have tended to be code that runs on each page load, like tabs.onUpdated, and not code that seems like it would only run once, like creating a context menu item with an icon - but you never know :-P

[chenba]

Talos results.

[jaredhirsch]

@chenba Great! Would you mind pinging jmaher in #perf to see if he thinks the results are ok?

[chenba]

jmaher said: "I think it is ok- the good news it is gave us data to look at- the orange/red items are that color because it looks like a possible or likely regression; in these cases by looking at the graphs and zooming in, you can see that most data points are bi-modal and on the try push it falls heavier on a single mode- therefore making the numbers different"

😌

We have Talos results and jmaher's input on them.

[jaredhirsch]

Thanks for following up with the Talos tests, @chenba. We'll have to keep this patch in mind if we see perf regressions in Nightly after our next export. Merging.